Horton

Re: [HACKERS] [PATCH] Generic type subscripting

Dmitry Dolgov <9erthalion6@gmail.com>

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From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Arthur Zakirov <a.zakirov@postgrespro.ru>
Cc: Oleg Bartunov <obartunov@gmail.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, David Steele <david@pgmasters.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-11-16T21:37:40Z
Lists: pgsql-hackers 
> On 16 November 2017 at 12:40, Arthur Zakirov <a.zakirov@postgrespro.ru>
wrote:
>
> Actually it is not only way to return isnull information.

What i've meant is that it's the only way if we want to keep the function
signature. Actually I would prefer this

    (container, internal) -> extracted value

over this (I assume that's exactly what you've suggested?)

    (container, internal, internal) -> extracted value

because it makes the purpose of the function more clear (especially for
custom
data types). Also it would be consistent with `assign` functions (since
`isnull` is not assigned there). But I see your point, a separate argument
for
`isnull` will make it more straightforward in terms of null handling.

> fetch() functions also doesn't need in ExprEvalStep struct

I had hard time parsing this, but from your examples I assume you're talking
about passing little bit different arguments to `fetch` function (am I
right?).
Just from functionality point of view I don't see a big difference in what
argument to use to return `isnull` by reference. So at the end I think we
need
to choose between having one or two `internal` arguments for `fetch`
functions.
Any other opinions?

Commits

  1. Throw error when assigning jsonb scalar instead of a composite object

  2. Filling array gaps during jsonb subscripting

  3. Implementation of subscripting for jsonb

  4. Allow ALTER TYPE to update an existing type's typsubscript value.

  5. Allow subscripting of hstore values.

  6. Support subscripting of arbitrary types, not only arrays.

  7. jit: Reference function pointer types via llvmjit_types.c.

  8. Teach contain_leaked_vars that assignment SubscriptingRefs are leaky.

  9. jit: Correct parameter type for generated expression evaluation functions.

  10. Renaming for new subscripting mechanism

  11. Fix assertion failure for SSL connections.

  12. Teach eval_const_expressions() to handle some more cases.